The contents of the following Japanese patent applications and PCT application are incorporated herein by reference:                NO. 2011-068374 filed on Mar. 25, 2011,        NO. 2011-129762 filed on Jun. 10, 2011, and        NO. PCT/JP2012/000938 filed on Feb. 13, 2012.        
1. Technical Field
The present invention relates to a light diffraction element and an optical low pass filter using the light diffraction element.
2. Related Art
An optical low pass filter is used for a digital movie or digital camera using an image capturing element in order to prevent Moire patterns caused by input of an optical image having a spatial frequency higher than the pixel pitch of the image capturing element. A liquid crystal board utilizing birefringence of a material is used as an optical low pass filter, as shown in Patent Document 1.
Patent Document 1: International Publication No. 2008/004570
However, a light diffraction element using a crystal board has an increased thickness, and is therefore difficult to miniaturize. Furthermore, a crystal board is expensive, and easily attracts debris due to its charge.